Method of developing silver halide photosensitive material

ABSTRACT

WHEREIN R1 and R2 are each an alkyl group having from 1 to 4 carbon atoms and each of X and Y is an alkoxyl group containing 1 or 2 carbon atoms or a chlorine atom.   A photographic developing process which comprises developing an exposed light-sensitive silver halide emulsion layer of a photographic material with an alkaline solution in the presence of hydroquinone and a derivative of a p-amino-phenol having the general formula:

ilite tates Arai et a1.

*5 atet [1 1 Mar. 25, 11975 METHOD OF DEVELOPING SILVER HALIDE PHOTOSENSITIVE MATERIAL Related US. Application Data [63] Continuation-impart of Ser. No. 192,954, Oct. 27,

1971, abandoned.

[30] Foreign Application Priority Data Oct 27, 1970 Japan 45-94883 [52] US Cl 96/66.3, 96/66 R, 96/95 [51] Int. Cl G03c 5/30, G03c 1/06 [58] Field of Search i. 96/66, 29, 95, 76

[56] References Cited UNlTED STATES PATENTS 3,108,001 10/1963 Green 96/66 R 3,600,176 8/1971 Haist et a1 96/66 R FOREIGN PATENTS OR APPLlCATlONS United Kingdom...

Primary ExaminerMary F. Kelley Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A photographic developing process which comprises developing an exposed light-sensitive silver halide emulsion layer of a photographic material with an alkaline solution in the presence of hydroquinone and a derivative of a p-amino-phenol having the general formula:

wherein R and R are each an alkyl group having from 1 to 4 carbon atoms and each 01X and Y is an alkoxyl group containing 1 or 2 carbon atoms or a chlorine atom.

17 Claims, 2 Drawing Figures TENTH) MAR 2 51875 35 ME: QZEZMRE ((1) MISNHG (G) MISNEK] METHOD OF DEVELOPING SILVER HALIDE PHOTOSENSITIVE MATERIAL This application is a continuation-in-part of US. Ser. No. 192,954 Arai, et al. filed Oct. 27, 1971, now abandoned and entitled Method of Developing Silver Halide Photosensitive Material.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of developing a silver halide photosensitive material. More particularly, it has an object in additionally improving the developing activity of hydroquinone by the use ofa developing agent comprising hydroquinone in combination with a specific type compound as hereinafter described.

2. Description of the Prior Art Photosensitive material has hitherto been prepared by coating a photosensitive silver halide emulsion on a substrate such as a glass plate, paper, a plastic film, etc., followed by drying the coated product. After the thus-prepared photosensitive material has been exposed to light, it is developed in a developer liquid which generally is an alkaline aqueous solution containing a developing agent as its essential ingredient, whereafter the developed material is subjected to stopping, fixation and water-rinsing treatments in sequence.

However, since these series of treatment processes require a fairly long period of time, a number of improvements have up to now been proposed so as to shorten the processing time. For instance, such an improved method includes high temperature processing, single-bath development and fixation, double bath stabilization treatment process, etc. One of the currently employed methods for shortening the time of development comprises adding a developing agent into the silver halide emulsion layer, then treating the layer in a highly alkaline aqueous solution containing an alkali agent and like other photographic additives such as antioxidants and retarders. The characteristic feature of that method resides in enabling a quick developing process with a shortened developing reaction time which is due to the use ofa processing liquid with a highly increased pH that can be only attained by the absence of a developing agent in the processing liquid without degrading the storability thereof. The silver halide photosensitive material to be suitably employed in that method includes silver chloride emulsions and silver chlorobromide emulsions having less silver bromide content which have high rates of developing reaction.

On the other hand, various attempts have been made to carry out similar quick processing even as to silver chlorobromide emulsions having higher silver bromide contents, pure silver bromide emulsions and silver iodobromide emulsions, by adding to these emulsions a developing agent. However, each of these silver chlorobromide emulsions, pure silver bromide emulsions and silver iodobromide emulsions have a slower developing reaction rate than a silver chloride emulsion, so that it has not been possible to obtain satisfactorily desirable photographic characteristics by treatment in a short period of time.

Meanwhile, it is well known in the art that excellent photographic characteristics, which have never been attained with the use of hydroquinone alone, can be obtained in usual development processes for silver halide photosensitive emulsions containing no developing 2 agent, by using a developer liquid containing hydroquinone and at the same time, together with a developing agent having super additivity such as l-phenyl-3- pyrazolidone or N-methyl-p-aminophenol (P0 or MQ developer). In addition it is disclosed in the specification of US. Pat. No. 2,751,279 thatthe rate ofdevelopment with MO developer is accelerated by the addition of l-phenyl-3-pyrazolidone to a silver halide emulsion.

By utilizing these prior teachings, the present inventors have made an attempt to accelerate the quick development of silver chlorobromide emulsions, silver bromide emulsions and silver iodobromide emulsions each containing a developing agent admixed therein. It was found, however, that the addition of these accelerators, i.e., 3-pyrazolidone, N-methyl-p-aminophenol, etc., to the emulsion is disadvantageous because these accelerator compounds are very liable to undergo oxidation which not only results in lowering the activity of the compound during storage of the sample but also discolors or contaminates the substrate base.

It was also reported that certain p-aminophenol derivatives such as compound (I) shown below, which is disclosed in Japanese Pat. Publication No. Sho 37-5993, and compound (II) shown below, which is disclosed in US. Pat. No. 3,265,499, have more excellent super additive power than the above-mentioned l-phenyl-3-pyrazolidone and N-methyl-p-aminophenol when they are used in combination with hydroquinone.

The present inventors have made an attempt so as to improve the above drawbacks encountered when using the compound described in the abovementioned United States Patent by adding these compounds to a photographic emulsion. However, an emulsion having incorporated therein these compounds is liable to generate fogging which leads to the other disadvantage that the developing speed appreciably decreases when trying to prevent the fogging by adding a known fog inhibitor.

Compounds (I) and (II), discussed above, have the general formula .ial

N Rz/ OH (I) wherein each of X and X is, for example, a hydrogen atom, a halogen atom, an alkyl group, an alkoxyl group, an alkylamino group, etc.

SUMMARY OF THE INVENTION The present inventors have now found that the aforesaid disadvantages can be obviated by the addition to a silver halide emulsion of a compound represented by the general formula (III) in combination with hydroquinone, and also that excellent photographic characteristics can be obtained by developing the photographic material with the use of a single hydroquinone developer. It has also been discovered that an alkaline developer liquid containing the compound shown by the general formula (III) and hydroquinone is an excellent photographic developing liquid.

ing the compound of the general formula (III) into any BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows the relationship between density and development time for several photographic materials. wherein each ofRl and R2 is an alkyl group having from FIG. 2 shows the relationship between reflection den- 1 to 4 carbon atoms and each of X and Y is an alkoxy my and developmg for the samples of Example group having I or 2 carbon atoms or Cl. DESCRIPTION OF THE PREFERRED A first object of this invention is to provide a photo- EMBODIMENTS graphlc devlopmg P a photogiaphlc mammal The novel developing agent of the above general forand an alkaline solution for photographic development 1 m b n d h f f b] hich P ovide a more rapid developing Speed without mu a may e usua y m t e Orm O a Sta 8 w d h h salt thereof such as hydrochloride or sulfate rather than any Ferease P Wlt an lmprfwemem p in the form of the free amine. More particularly, the graph: charactensncs y emplgymg, a Q S of compounds identified hereinafter have been proved to gemra] formula m com Ina/On with a y be very suitable for being applied in the process acqumone f cording to the present invention:

A second ob ectof this lnventton is to provide a ph o- 4 di n propylamino 2,6 dimethoxyphenol hydro tographic developing process, a photographic material chloride and an alkaline solution for photographic development 4 dimethylamino zbdimethoxwhenol hydro which provide a more rapid Initiation of development chloride than Obtained y the p r art Without t decrease 3. 4-di-n-butylamino-2,o-dimethoxyphenol sulfate Q'I with all lmpt'ovemcnt In, photographic characterls- The ompound represented formula is em. P y pl y Compound P general formula ployed with hydroquinone in the process, material andm combination with a hydroq in n developer /or alkaline solution ofthe present invention as follows:

Amount per mole of light-sensitive silver Proportion Compound halide or pcr liter of thcrcbctwccn to be added To alkaline solution by weight hydroquinone layer 5 to 500 rams l Compound (lll) layer 0.05 to 5 grams H100 to l/lO hydroquinone layer 5 to 500 grams Compound (Ill) solution 0.0l to 20 grams hydroquinone solution I to 70 grams Compound (Ill) layer 0 0| to grams hydroquinone solution I to 70 grams 1 Compound (Ill) solution 0 ()l to 20 grams 1/100 to 1/10 A fourth object of this invention is to employ a compound of the general formula (III) as an essential developing agent having super additivity when combined with hydroquinone for developing monochromic and color photographic elements.

A fifth object of this invention is to accelerate developing speed upon usual developing treatment by add- The compound represented by the general formula (III) is effective for the combination with either pure silver chloride, silver chlorobromide, pure silver bromide or silver iodobromide, but an outstanding effect is attained when it is combined with silver chlorobromide, pure silver bromide or with silver iodobromide emulsions, each of which is known to have slow developing activity.

The developing agent to be used in combination with the compound of the general formula (III) in accordance with the present invention is not limited to any specific type, but it is possible to use any compound which is conventionally used as a photographic developing agent having reducing activity. Examples of such developing agents include hydroquinone or its derivatives, catechol or its derivatives, ascorbic acid, etc.

The substrate to be used for supporting the silver halide photographic material may be any one of those materials which can be coated with the silver halide emulsion layer and typically include paper, plastic films, etc., which may be further provided with a baryta layer or an undercoat layer.

The silver halide emulsion to be used includes a silver halide photosensitive material, and may contain gelatin or other synthetic resins such as poly(vinyl alcohol), poly(vinyl acetyl), etc., as a binder.

Since the compound represented by the general formula (111) is a novel compound, suitable methods for its preparation will be explained in detail.

Synthesis Example 1 4-Dimethylamino-2,6-dimethoxyphenol hydrochloride In accordance with a conventional method (e.g., .Iikken Kagaku Koza, 17, (A), pp. 509), 2,6- dimethoxyphenol was coupled with a diazonium salt of sulfanylic acid to give an azo dye which was subsequently reduced with sodium hydrosulfite to give 4-amino-2,6-dimethoxyphenol. A one-liter autoclave was charged with 23.5 g of the thus prepared 4-amino-2,6-dimethoxyphenol, 30 ml of a 37% aqueous formalin solution, palladium-carbon and 600 ml. of ethanol, then brough to a hydrogen pressure of 23 atmospheres, and stirred for two days at room temperature under continuous stirring so as to effect complete absorption of hydrogen. After filtering the reaction product and removing ethanol from the filtrate by distillation under reduced pressure, the residual substance was distilled under reduced pressure. The fraction boiling at l28l32C collected was dissolved in about one liter of ether, then dry hydrogen chloride gas was introduced to the resulting solution to give 22.0 g (yield of 70.0%) of white powdery crystals of the desired compound which was recrystallized from ethanol to give a colorless crystal.

SYNTHESIS EXAMPLE 2 4-Dimethylamino-2,6-dimethoxyphenol hydrochloride A mixture comprising 32.0 g of 4-amino-2,6- dimethoxyphenol prepared in a manner similar to the preceding Synthesis Example 1, 59.0 g of ethyl iodide, 26.0 g of anhydrous potassium carbonate and 400 ml of ethanol was heated under reflux for two hours in a nitrogen atmosphere with stirring. After cooling the reaction product mixture to room temperature, it was filtered under suction and the solid mass which remained on the filter paper was washed twice with ethanol. The filtrate and wash liquid were combined together and freed from ethanol. The filtrate and wash liquid were combined together and freed from ethanol by distillation under reduced pressure to leave a residue which was then moistened twice with ether. After removing ether, it was distilled under reduced pressure to thereby collect a fraction boiling at l73-181C/1 mm Hg. This fraction was dissolved in about 500 ml of ether and dry hydrogen chloride gas was introduced to the resulting solution to give 17.5 g (yield of 35.5%) of white powdery crystals of the desired compound, recrystallization of which from a mixed solvent containing a small amount of dilute hydrochloric acid gave a colorless crystal.

SYNTHESIS EXAMPLE 3 4-Diethylamino-2,6-dichlorophenol hydrochloride A 500 ml autoclave was charged with 20.8 g of 4- nitro-2,6-dichlorophenol, l 1.0 g of an aqueous acetaldehyde solution, 1.0 g of 10% Pd-C and ml of ethanol, and brought to a hydrogen pressure of 60 atmospheres and stirred at room temperature for about 4 hours until complete absorption of hydrogen was effected. After filtering the reaction product mixture, the filtrate was distilled under reduced pressure to remove ethanol and the residue was distilled under reduced pressure. The fraction boiling at -183C/2 mm Hg was collected and dissolved in about 500 ml of ether. To the resulting solution, dry hydrogen chloride gas was introduced to give 9.2 g (yield of 33.9%) of white powdery crystals of the desired compound which was recrystallized from dilute hydrochloric acid to give sublimative crystals of a tetragonal system.

The present invention will be explained in further detail by reference to the following examples, which are intended to be merely illustrative, and not limiting, in nature.

EXAMPLE 1 Photographic baryta paper of l50g/m was coated with a solution containing 400 cc ofa silver halide gelatin emulsion comprising 50g of gelatin and 20g of silver chlorobromide ofa silver bromide content of 60 mol a necessary hardening agent, coating additives and each developing agent as shown in Table 1. The thuscoated paper was further coated, under a set state before drying of the coated emulsion layer, with a protective layer consisting of 20g of gelatin, 6cc of saponin (as a 6% methanol solution) and one liter of water, and thereafter dried to prepare samples A to I shown in Table 1. Each sample was then exposed to light through an optical wedge (step wedge) and developed with an activated solution having a composition as follows:

Composition of Activated Solution:

Anhydrous sodium sulfite 45g Potassium hydroxide 48g Potassium bromide 1.3g Water to make the entire solution to l000cc.

Each was further treated with a stabilizing liquid containing ammonium thiocyanate (NH SCN). The photographic characteristics so obtained are shown in Table 1.

l0g Hydroquinonc 0.53 Mctol Table l-Continued As is noted from Table 1, it is understood that samples G, H and l, to which the compound of this invention was added, exhibit outstandingly high values in sensitivity, maximum density and gamma, when compared to the other samples.

EXAMPLE 2 A coating solution was prepared by adding the necessary hardening agent and coating additives to 400 cc of a silver halide gelatin emulsion containing 50g of gelatin and g of silver iodobromide in which silver iodide occupied 1.5 mol%. This coating solution was applied to photographic baryta paper of 150 g/m The coated paper was then further coated, under a set state before drying of the coated emulsion layer, with a coating solution comprising 20g of gelatin, a mixture of 30g of hydroquinone and 1.5g of 4-diethylamino-2, 6- dimethoxyphenol hydrochloride as an essential developing agent, 2g of sodium benzene sulfinate as an antioxidant for the developing agent, 3cc ofa 30% aqueous formalin solution, 6cc of a 6% methanol solution of saponin and one liter of water and thereafter dried.

A comparative sample was similarly prepared without adding the above 4-dimethylamino-2, 6- dimethoxyphenol hydrochloride thereto.

The thus-prepared paper samples were treated according to the manner described in Example 1. The sample of this invention exhibited superior values in every case of sensitivity, maximum density and gamma to the control sample.

EXAMPLE 3 Photographic baryta paper of l50g/m was coated with a coating solution comprising 50g of gelatin, 35g of hydroquinone, 2.0g of 4-diethylamino-2, 6- dichlorophenol hydrochloride, 2g of sodium benzene sulfinate as an antioxidant for the hydroquinone, 2cc of a 30% aqueous formalin solution, 1.0g of a fluoroescent whitening agent Blankophor BUP (Trade name, manufactured by Bayer Co., West Germany)" and 1 liter of water, upon which there was coated a coating solution comprising 400cc of a silver halide gelatin emulsion containing 20g of silver chlorobromide in which the content of silver bromide was 60 mol and other necessary additives such as a hardening agent and coating additves. The thus-coated paper was further provided, under a set state before drying of the coated emulsion layer, with a protective layer by coating thereon a solution comprising 20g of gelatin, 6cc of a 6% methanol solution of saponin and one liter of water.

On the other hand, a control sample was similarly prepared but adding no 4-diethy1amino-2, 6- dichlorophenol hydrochloride in the abovementioned composition.

Both samples (photographic paper) thus-prepared were subjected to similar treatments to those described in Example 1. It was noted that the sample prepared according to this invention, i.e., having 4-diethylamino-2, 6-dichlorophenol added to the undercoat layer thereof, exhibited excellent properties with extremely higher values in every case of sensitivity, maximum density and gamma than those obtained with the control sample.

EXAMPLE 4 A coating solution was prepared by adding the necessary hardening agent and coating additives to 400 cc of a silver halide gelatin emulsion containing 20g ofsilver chlorobromide with a silver bromide content of 50 mol% and 50g of gelatin. The coating solution was applied to photographic baryta paper of g/cm to prepare a photographic paper. This paper was developed with the use of the developing liquid having the following composition and the change in darkening concentration in relation to the developing period at a constant exposure dosage is shown in the FIG. 1.

The FIG. 1 illustrates the relationship of density to developing time of the samples obtained according to this invention and comparative samples:

4-diethylamino-2,tS-dichlorophenol hydrochloride Composition of Developing Bath (PH 10.9)

Anhydrous sodium sulfitc 20g Hydroquinone 3g Anhydrous sodium carbonate 15g Potassium bromide 1g -Continued Combined developing agent of the above table (molar ratio of 1/20 to hydroquinone) Water to make the entire solution to 1000cc.

It will be understood from the curves illustrated in the FIG. 1 that the compound of this invention has extremely high super additivity for developing activity.

EXAMPLE Photographic baryta paper of 150 g/m was coated with a coating solution prepared by adding 30g of hydroquinone and other requisite additives to every one Kg of a silver halide emulsion containing 40g of silver chlorobromide (60 mol silver bromide) per 125g gelatin, then dried. The thus-prepared photographic paper was exposed to light through a step wedge, then developed for 4 seconds with the activated Solution used in Example 1, thereafter stabilized with a stabilizer solution containing ammonium thiocyanate. For the purpose of comparison, the same treatement was carried out but using instead an activated solution containing 0.9g of the compound of Synthesis Example 1 per liter of the solution. The results after measuring specific sensitivity, maximum density and gamma are presented in Table 2.

Synthesis Example l As is noted from the results in the above table, the compound of Synthesis Example 1 proved to greatly accelerate the developing activity of hydroquinone.

EXAMPLE 6 Photographic baryta paper of 150 glcm was coated with an emulsion containing 2.3 g of the compound of Synthesis Example 2 and the other requisite additives per Kg of the silver halide emulsion of Example 5, then dried to give a photographic paper. This photographic paper and another photographic paper prepared by using an emulsion without containing the compound of Synthesis Example 2 were each exposed to light through a step wedge, then developed for 4 seconds with an activated solution containing g of hydroquinone per liter of the solution shown in Example 1, and thereafter stabilized by a stabilizer solution containing ammonium rhodanate. The results obtained by measuring the specific sensitivity, maximum density and Table 3'-Continued Specific Maximum Sensitivity Density Gamma Paper containing the compound of Synthesis Example 2 15.50 1.25 1.6-3

It will be noted from these results that the addition of the compound of Synthesis Example 2 greatly enhances the development by hydroquinone.

EXAMPLE 7' This example was performed to compare the present invention to that disclosed in British Pat. No. 1,214,105 and Belgian Pat. No. 737,795.

A coating solution was prepared in accordance with Example 4 above except for using silver bromoiodide with a silver bromide content of 97.6 mol and a silver iodide content of 2.4 mol The coating solution was applied onto a triacetyl cellulose base of ISO/cm to prepare a photographic paper. The paper was devel oped with the use of the two most typical developing liquids used in the art to test and evaluate a superadditive effect [described by J. F. Willems, et al. in Photographic Science and Engineering, 10 (6). 316 (1966)]. The results obtained are shown in the tables below:

Developing Liquid A Sodium Carbonate (calculated as Na CO fl o) 23.4 g Sodium Hexametaphosphate 1 g Sodium Sulflte 20 g Potassium Bromide 0.5 g Hydroquinone 4.4 g Aminophenol Derivative* 1 X 10 mol Water to make 1000 ml Developing Liquid B Boric Acid 5 g Borax 10 g Sodium Hexametaphosphate 1 g Sodium Sulfite 20 g Potassium Bromide 0.5 g Hydroquinone 4 4 g Aminophenol Derivative* 1 X 10 mol Water to make 1000 ml As the aminophenol derivative: (a) 4-(N.N-diethylamino1-2.6-dimethoxyphenol hydrochloride called for in the present application; and (h) 4-(N.N-diethylamino)-2,6-xylenol hydrochloride recited in the British patent or Belgian equivalent thereto were employed as representative materials, respectively. The former aminophenol is substituted with methoxy groups. whereas the latter is substituted with methyl groups, at the 2- and 6- positions thereof.

*As the aminophenol derivative: (a) 4-(N,N- diethylamino)-2,6-dimethoxyphenol hydrochloride called for in the present application; and (b) 4-(N,N- diethylamin0)-2,6-xylenol hydrochloride recited in the British patent or Belgian equivalent thereto were employed as representative materials, respectively. The former aminophenol is substituted with methoxy groups, whereas the latter is substitued with methyl groups, at the 2- and 6-positions thereof.

Table l (pH=lO.4)

Aminophenol Developing (a) time (seconds) Table 2 (pl-l=8.7)

Aminophenol Developing (a) time (minutes) Curve A:

Curve B Developing Agent Composition of the Developing Bath (pH 10.9)

Anhydrous sodium sulfite 20 g Composition of the Developing Bath (pH 10.9)

Hydroquinone 3 g Anhydrous sodium carbonate 15 g Potassium bromide l g Developing agent as in the table (molar ratio: 1/15 to hydroquinone).

Water to make 1000 cc Change in Density in Relation to Developing Period 30 60 1 Z40 4-dimcthylamino-2,6 0,10 0.81 1.47 1.74 dimethoxyphenol hydrochloride (present invention) 4-diethylamino-2,6- O 0.59 1.13 1.3;

xylcnol hydrochloride (disclosed in British Patent 1,241,105)

The values in Table 1 and Table 2 are given in terms of the developing speed which is expressed by transmittance density/developing time. The higher this value, the shorter the time required to form an image.

From the results shown in the tables above, it is seen that the combination of the present application shows a superior developing speed to that of the aminophenol disclosed in the prior art references. In particular, when the system is developed with developing liquid B which exhibits strong alkalinity, the developing speed of the system in accordance with the present invention is almost 6 times (after 1 minute of development) that of the prior art. Such rapid image formation is an extremely desirable characteristic in development using an automatic camera system since it enables short developing time. This tendency of rapid development with respect to the combination claimed in the present application is observed through the developing time for both developing liquids A and B.

Thus, it was found that the combination of aminophenol (a) and hydroquinone has a surprising superadditive effect for use in a photographic developing process.

EXAMPLE 8 A coating solution was prepared by adding the necessary hardening agent and coating additives to 400 cc of a silver halide gelatin emulsion containing 20 g of silver chlorobromide with a silver bromide content of mol and 60 g ofgelatin. The coating solution was applied to photographic baryta paper of 150 g/cm to prepare As is seen from the results obtained above, not only is the initiation of development slower with the combination of the British Patent than with the present invention, but also the combination of the British Patent shows a low developing activity. In the super additive combination of the present invention, development proceeds rapidly and excellent developing activity is exhibited.

EXAMPLE 9 When Example 5 of British Pat. No. 1,241,105 was duplicated except for using 1/20 of a mol of developing agents as described in Example 8 per mole of hydroquinone, a relationship similar to that of Example 8 was also observed at a somewhat higher density level. This is, the combination of the present invention exhibited a faster initiation of development and a higher developing activity than the combination of the British Patent.

An increase in developing speed greatly influences the commercial value of a product. For instance, short developing speed is a key factor in an automatic camera system. In general, a shorter developing time and rapid completion of development are preferred in the art since problems such as accidental changes in developing conditions can be avoided.

It will be clearly understood that the present invention is not only adaptable for a silver halide photosensitive material containing a developing agent in the emulsion layer thereof. but also quite similarly applicable with excellent results to conventionally used silver halide photosensitive materials for photographic or copying use containing no developing agent in their emulsion layer.

wherein R and R are each an alkyl group having from 1 to 4 carbon atoms and each of X and Y is an alkoxyl group containing 1 or 2 carbon atoms or a chlorine atom, or a stable salt thereof.

2. The photographic developing process of claim 1, wherein said hydroquinone is present in said emulsion layer or in a layer adjacent thereto and said derivative is incorporated in said alkaline solution.

3. The photographic developing process of claim 1, wherein said hydroquinone is present in said alkaline solution, and said derivative is present in said emulsion layer or in a layer adjacent to said emulsion layer.

4. The photographic developing process of claim 1, wherein said hydroquinone and said derivative are present in said emulsion layer or in a layer adjacent thereto.

5. The photographic developing process of claim 1, wherein said hydroquinone and said derivative are present in said alkaline solution.

6. The photographic developing process of claim 2, wherein the amount of said hydroquinone is from 5 to 500 grams per mole of light-sensitive silver halide.

7. The photographic developing process of claim 4, wherein the amount of said hydroquinone is from 5 to 500 grams per mole of light-sensitive silver halide.

8. The photographic developing process of claim 3, wherein the amount of said derivative is from 0.05 to 50 grams per mole of light-sensitive silver halide.

9. The photographic developing process of claim 4, wherein the amount of said derivative is from 0.05 to 50 grams per mole of light-sensitive silver halide.

10. The photographic developing process of claim 3, wherein the amount of said hydroquinone is from 1 to 70 grams per liter of alkaline solution.

11. The photographic developing process of claim 5,

wherein the amount of said hydroquinone is from 1 to grams per liter of said alkaline solution.

12. The photographic developing process of claim 2, wherein the amount of said derivative is from 0.01 to 20 grams per liter of said alkaline solution.

13. The photographic developing process of claim 5, wherein the amount of said derivative is from 0.01 to 20 grams per liter of said alkaline solution.

14. The photographic developing process of claim 1,

wherein said derivative is 4-di-n-propylamino-2,6-dimethoxyphenol hydrochloride, 4-dimethylamino-2,6-dimethoxyphenol hydrochloride or 4-di-n-butylamino-2,6-dimethoxyphenol sulfate.

15. The photographic developing process of claim 1 wherein said derivative is employed in the form of a stable salt thereof.

16. A photographic element having at least one lightsensitive silver halide emulsion layer, which element contains hydroquinone and a derivative of paminophenol having the general formula wherein R and R each is an alkyl group having from 1 to 4 carbon atoms and each of X and Y is an alkoxyl group containing 1 or 2 carbon atoms or a chlorine atom, said derivative of p-aminophenol illustrating a super-additive development effect in combination with hydroquinone. 

1. A PHOTOGRAPHIC DEVELOPING PROCESS WHICH COMPRISES DEVELOPING AN IMAGEWISE EXPOSED LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER OF A MULTILAYER PHOTOGRAPHIC ELEMENT WITH AN ALKALINE SOLUTION, HYDROQUINONE AND A DERIVATIVE OF P-AMINOPHENOL HAVING THE GENRAL FORMULA:
 2. The photographic developing process of claim 1, wherein said hydroquinone is present in said emulsion layer or in a layer adjacent thereto and said derivative is incorporated in said alkaline solution.
 3. The photographic developing process of claim 1, wHerein said hydroquinone is present in said alkaline solution, and said derivative is present in said emulsion layer or in a layer adjacent to said emulsion layer.
 4. The photographic developing process of claim 1, wherein said hydroquinone and said derivative are present in said emulsion layer or in a layer adjacent thereto.
 5. The photographic developing process of claim 1, wherein said hydroquinone and said derivative are present in said alkaline solution.
 6. The photographic developing process of claim 2, wherein the amount of said hydroquinone is from 5 to 500 grams per mole of light-sensitive silver halide.
 7. The photographic developing process of claim 4, wherein the amount of said hydroquinone is from 5 to 500 grams per mole of light-sensitive silver halide.
 8. The photographic developing process of claim 3, wherein the amount of said derivative is from 0.05 to 50 grams per mole of light-sensitive silver halide.
 9. The photographic developing process of claim 4, wherein the amount of said derivative is from 0.05 to 50 grams per mole of light-sensitive silver halide.
 10. The photographic developing process of claim 3, wherein the amount of said hydroquinone is from 1 to 70 grams per liter of alkaline solution.
 11. The photographic developing process of claim 5, wherein the amount of said hydroquinone is from 1 to 70 grams per liter of said alkaline solution.
 12. The photographic developing process of claim 2, wherein the amount of said derivative is from 0.01 to 20 grams per liter of said alkaline solution.
 13. The photographic developing process of claim 5, wherein the amount of said derivative is from 0.01 to 20 grams per liter of said alkaline solution.
 14. The photographic developing process of claim 1, wherein said derivative is 4-di-n-propylamino-2,6-dimethoxyphenol hydrochloride, 4-dimethylamino-2,6-dimethoxyphenol hydrochloride or 4-di-n-butylamino-2,6-dimethoxyphenol sulfate.
 15. The photographic developing process of claim 1 wherein said derivative is employed in the form of a stable salt thereof.
 16. A photographic element having at least one light-sensitive silver halide emulsion layer, which element contains hydroquinone and a derivative of p-aminophenol having the general formula
 17. AN ALKALINE SOLUTION FOR PHOTOGRAPHIC DEVELOPMENT WHICH CONTAINS HYDROQUINONE AND FROM 0.01 TO 20 GRAMS PER LITER OF SAID SOLUTIONN OF A DERIVATIVE OR P-AMINOPHENOL HAVING THE GENERAL FORMULA: 